package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.FOLLOW_KEY;


@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IUserService userService;

    /**
     * 关注
     * @param followUserId
     * @param isFollow
     * @return
     */
    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        //获取登录用户
        Long userId = UserHolder.getUser().getId();
        String key = FOLLOW_KEY + userId;
        //1.判断到底是关注还是取关
        if(isFollow){
            //2.关注，新增数据
            Follow follow = new Follow();
            follow.setUserId(userId);
            follow.setFollowUserId(followUserId);
            boolean isSuccess = save(follow);
            if(isSuccess){
                //用户关注消息保存成功，把关注的用户id放入redis的set集合
                stringRedisTemplate.opsForSet().add(key,followUserId.toString());
            }
        }else{
            //3.取关，删除 delete from tb_follow where user_id = ? and follow_user_id = ?
            boolean isSuccess = remove(new QueryWrapper<Follow>()
                    .eq("user_id", userId).eq("follow_user_id", followUserId));
            if(isSuccess){
                //把关注用户的id从redis的set集合中移除
                stringRedisTemplate.opsForSet().remove(key,followUserId.toString());
            }
        }
        return Result.ok();
    }

    /**
     * 取消关注
     * @param followUserId
     * @return
     */
    @Override
    public Result isFollow(Long followUserId) {
        //获取登录用户
        Long userId = UserHolder.getUser().getId();
        //1.查询是否关注 select count(*) from tb_follow where user_id = ? and follow_user_id = ?
        Integer count = query().eq("user_id", userId).eq("follow_user_id", followUserId).count();
        //2.判断
        return Result.ok(count > 0);
    }

    /**
     * 共同关注
     * @param id
     * @return
     */
    @Override
    public Result followCommons(Long id) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        //当前登录用户的关注列表集合
        String key1 = FOLLOW_KEY + userId;
        //点击查看的用户的关注列表集合
        String key2 = FOLLOW_KEY + id;
        //2.求交集 查询当前用户与目标用户的共同关注对象
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(key1, key2);
        if(intersect == null || intersect.isEmpty()){
            //无交集
            return Result.ok(Collections.emptyList());
        }
        //解析id集合
        List<Long> ids = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
        //批量查询用户并转换为UserDTO对象
        List<UserDTO> userDTOList = userService.listByIds(ids).stream().map(user ->
                        BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(userDTOList);
    }
}
